Which has more kinetic energy, a 1400 kg car moving at 115 km/h or a 12,000 kg truck moving at 38 km/h?

Video transcript

Hey everyone, we're asked to determine the object with a higher kinetic energy between a snowmobile with a mass of 227.8 kg, moving at 67m/s or a truck with a mass of 15,000 kg, moving at 28 km/h. To answer this question, we need to use the formula kinetic energy equals half mass times velocity squared. So first, let's go ahead and look at a where we have a snowmobile with a mass of 227.8 kg And our velocity is 67 m/s. plugging in these values, we get our kinetic energy is equal to half times 227.8 kg Times 67m/s squared. Now, when we calculate this out, we end up with a value of 511,297 kg times meters squared over second squared. Now let's go ahead and look at B. So for B we have a mass of 15,000 kg and we have a velocity of 28 kilometers per one hour. Now we want to convert this into meters per second to do so we can use our dimensional analysis and we know that Per one km we have 10 to the 3rd m And per one hour we have 3600 seconds. So when we calculate this out and cancel out all of our units, We end up with a velocity of 7.7778 meters per second. Now let's go ahead and plug in our values. So we have half times our mass, which is 15,000 kg times our velocity squared which is 7.7778 m/s squared. So when we calculate this out, we end up with 453,706 kg times meters squared over second squared. Now when we compare these two values, we can see that our snowmobile has a higher kinetic energy. So our answer here is going to be snowmobile has the higher kinetic energy. Now, I hope this made sense and let us know if you have any questions.